Dimeric prenylated C6-C3 compounds from the stem bark of Illicium oligandrum

Chemical constituents from the stem bark of Illicium burmanicum and their anti-inflammatory activity

Thirty-six compounds were isolated from extract of the stem bark of Illicium burmanicum, including twelve previously undescribed prenylated C6-C3 compounds and a norsesquiterpene lactone: illicidione D (1), illicidione E (2), illicidione F (3), illicidione G (4), (2R,4S,11R)-12-O-ethylillifunone C (5), (2R,4S,11R)-illifunone C-12-O-β-d-glucopyranoside (6), (2R,4S,11R)-2-hydroxyillifunone C (7), 4-epi-2,3-dehydroillifunone C (8), illiburmanone A (9), illiburmanone B (10), illiburmanlactone A (11), (2S,4S,5S,11R)-2,3-dihydroillicione E (12), and illiburmanolside A (13). Their structures were determined based on extensive spectroscopic data analyses, including MS, NMR, and ECD spectra. The anti-inflammatory activity of the isolated compounds (1-36) was evaluated, and compounds 7, 12, 14, and 18 exhibited inhibitory effects in RAW 264.7 cells induced by LPS.

Prenylated C6-C3 derivatives from the root of Illicium ternstroemioides with antiviral activity

Six previously undescribed prenylated C6-C3 derivatives (1-6) were isolated from the root of Illicium ternstroemioides A. C. Smith. Their structures were elucidated based on extensive spectroscopic analyses (UV, IR, 1D and 2D NMR, and HRESIMS). The absolute configurations of 1-3 were determined using electronic circular dichroism (ECD), and Mo2(OAc)4 induced circular dichroism (ICD). Compound 3 exhibited weak activity against Coxsackievirus B3 with an IC50 value of 33.3 µM, and compound 5 exhibited more potent activity against Coxsackievirus B3 with an IC50 value of 6.4 µM.

Diverse prenylated C6-C3 derivatives from the stems and branches of Illicium ternstroemioides A. C. Smith with anti-inflammatory and antiviral activities

Fifteen unreported prenylated C6-C3 derivatives (1-15) were isolated from the stems and branches of Illicium ternstroemioides A. C. Smith, including one bis-prenylated C6-C3 derivative (1), three prenylated C6-C3 derivative-shikimic acid ester hybrids (2-4) and 11 prenylated C6-C3 monomers (5-15). The structures of compounds 1-15 were elucidated by spectroscopic analysis (UV, IR, 1D and 2D NMR, and HRESIMS). The absolute configurations of the compounds were determined using electronic circular dichroism (ECD), induced circular dichroism (ICD), and the modified Mosher's method. Among the isolates, compounds 11, 12, and 15 exhibited significant anti-inflammatory activities by inhibiting the nitric oxide with IC50 values ranging from 1.89 to 24.83 μM in lipopolysaccharide-stimulated murine RAW 264.7 macrophages and murine BV2 microglial cells; compounds 2, 3, and 7 exhibited antiviral activitives against Coxsackievirus B3 with an IC50 value of 33.3, 25.9, and 27.8 μM, respectively.

Bergamotane-type sesquiterpenes from the leaves and twigs of Illicium oligandrum and their anti-inflammatory activities

Eight undescribed β-bergamotene-type sesquiterpene oliganins A-H (1-8) and one known α-bergamotene-type sesquiterpene (9) were isolated from the leaves and twigs of Illicium oligandrum Merr. & Chun. The structures of compounds 1-8 were elucidated by extensive spectroscopic data, and the absolute configurations were determined by using a modified Mosher's method and electronic circular dichroism calculations. The isolates were further evaluated in terms of their anti-inflammatory potential on nitric oxide (NO) generation in lipopolysaccharide-stimulated RAW264.7 and BV2 cells. Compounds 2 and 8 exhibited potent inhibitory effects on the production of NO with IC₅₀ values ranging from 21.65 to 49.28 μM, which were greater than or comparable to those of dexamethasone (positive control).

Methylene-bridged dimeric natural products involving one-carbon unit in biosynthesis

This review summarizes the methylene-bridged dimeric natural products involving one-carbon unit in biosynthesis, including their structures, biological activities, synthetic methods, and formation mechanisms.

Prenylated C6-C3 derivatives from the stems and branches of Illicium ternstroemioides A. C. Smith with antiviral activity

Thirteen compounds were isolated from the lipid-soluble extracts of Illicium ternstroemioides A. C. Smith, including eleven previously undescribed prenylated C₆-C₃ compounds, a previously undescribed prenylated C₆-C₃ derivative-abscisic acid ester hybrid, and a known compound (4S)-illicinone I. Their structures and configurations were mainly elucidated by spectroscopic analyses, CD experiments and X-ray crystallography. (2S,4R,11S)-4-O-methyl-12-chloroillifunone C, (2S,4R,11R)-2,3-dihydro-4-O-methyl illioliganfunone D, and illiternfunol A were found to exhibit weak activity against Coxsackievirus B3, with IC₅₀ values ranging from 27.8 to 33.3 μM. Illiternone B exhibited more potent activities against Coxsackievirus B3 and influenza virus A than did its geometric isomer illiternone A, with IC₅₀ values of 7.7 μM and 2.5 μM, respectively. None of these compounds displayed cytotoxic activities.

Library construction of stereochemically diverse isomers of spirooliganin: their total synthesis and antiviral activity

The construction of libraries of stereoisomers of natural products serves as an important approach to investigating the correlation between the stereostructure and biological activity. However, the total synthesis and isomerzation of polycyclic scaffolds with multiple chrial centers are rare. Spirooliganin (1), a new skeleton natural product isolated from the plant Illicium oligandrum, was structurally characterized by comprehensive analysis of NMR spectroscopic data and ECD which revealed an unprecedented 5-6-6-6-7 polycyclic framework with six chiral centers. Here we report a 17-step total synthesis to prepare a library of stereochemically diverse isomers of spirooliganin, including 16 diastereoisomers and 16 regioisomers. In addition to a regioselective hetero-Diels-Alder cycloaddition, the synthetic strategy involves a photo-induced stereoselective Diels-Alder reaction, which gives only the abnormal trans-fused product as rationalized by density functional theory calculations. Preliminary biological evaluation showed that spirooliganin and regioisomers 39 exhibited potent inhibition of Coxsackievirus B3. It also revealed the pharmacophore effect of the D-ring (16R,18R,24R, and 26R) for their antiviral activities.

Prenylated phenylpropanoid compounds from the stem bark of Illicium burmanicum

Ten new prenylated phenylpropanoid compounds, burmanicumols A-G (1-6) and illifrognones D-G (7-10), and seven known prenylated phenylpropanoid compounds, were isolated from the stem bark of Illicium burmanicum. The structures of the new compounds were determined on the basis of 1D and 2D NMR, HRESIMS, and CD experiments. Compounds 3, 8, 10, and 14 were moderately potent inhibitors of the NF-κB pathway, with IC50 values ranging from 10.31 to 35.16μg/mL tripterygium glycosides and pavlin were used as the positive controls.

Sesquiterpenes from the roots of Illicium oligandrum

Two new sesquiterpenes, oligandrin (1) and oligandric acid (2), together with three analogues, tashironin A (3), tashironin (4), and oplodiol (5), were isolated from the roots of Illicium oligandrum. The structures of new compounds were determined based on 1D and 2D NMR experiments and X-ray diffraction. Compound 1 represents a presumed biosynthetic precursor of seco-prezizaane sesquiterpenes which consists of a novel 6/6/5 tricarbocyclic skeleton. Compound 2 is the first example of chamipinene-type sesquiterpene possessing a 6/4/6 tricyclic system from the genus Illicium. Compounds 1-5 were evaluated in vitro for their activity against coxsackie virus B3 (CVB3), influenza virus A/Hanfang/359/95 (H3N2), and influenza virus A/FM/1/47 (H1N1). Compound 1 showed selective antiviral activity against CVB3 with IC50 value of 11.11 μM.

Diterpenoids and sesquiterpenoids from the roots of Illicium majus

Five new diterpenoids (1-5), five new sesquiterpenoids (6-10), and three known compounds (11-13) were isolated from the roots of Illicium majus. Their structures were elucidated by extensive spectroscopic analysis. The absolute configuration of 1 was assigned by X-ray crystallography, whereas those of the 1,2-diol moieties in 3 and 4 were determined using Snatzke's method. The abietane acids 1, 2, 11, 12, and 13 displayed antiviral activity against the Coxsackie B3 virus, with IC50 values of 3.3-51.7 μM/mL.

Natural products chemistry research: progress in China in 2011

This article reviews the progress made by Chinese scientists in the field of natural products chemistry in 2011. Selected compounds with unique structural features and/or promising bioactivities are described herein on the basis of structural types.